Line welding



BEST AVAILABLE com Oct. 5 1926.

.H. w. TOBEY LINE WELDING Filed August 27, 1923 2 Sheets-Sheet 1 hllllllllllllllllll H11] [llllllllllll] Ihx/ennor: Harrg W Tob/e 9;

His Attorney.

BEST AVAfLABLE com Oct. 5 1926 1,601,927

. H. w. TOBEY LINE WELDING Filed August 7. 1923 2 Sheets-Sheet 2 5.

/8 .7" fi L I 2 u 3 I] a Inventor: Harr-l w'l'obea;

His Aptorneg- Patented Oct. 5, 1926.

BEST AVAILABLE'COP.

res-1,922 PATENT; eer e-E.

- HARRY W. TOBEYtOElITTSFIELD, MASSACHUSETTS; ASSIGFFOR' '10 GENERAL ELI JG TRIO COMPANY, A. CORPORATION OF NEW YORK.

LINE- WELDINGA ApplieationUfled August 27, 1923.. Serial No. (55 ,452.

My invention relates to electric weldingoi the type wherein a line weld made by passingv thewor-k between a pair of rotatable disk electrodes which conduct current into the Work to bring the. parts to bewelded to a welding temperature, the electrodes of welding. This type of vweldingfis well any'oth'erl means to pressnpon or swage the joint, My. invention more particularly ,relatesto the production of circumferential welds. of the type. encountered, for example in weldingithe head'oiiia drum or. tank, or the welding together. of .sections of such articles but .certain. features are of broader .ap =plicationi. 4 Anobject. ofQmy invention. isto PIOVIdQ an and without prodiicing. a. deleterious effect Another object ofmy invention is to pr0- vide an. arrangement of parts which. will -lessen the tendency of thework to creep late as erally-wi th respect-to the electrodes.and-arrangements of apparatus whereby .s-uch creeping may be counteracted.

My inventionwill be better understood from the following description taken in .con- 05 nection. with the accompanying drawings,

and. its scope will be pointed out in theappended claims;

In the drawings, Fig. 1 represents anembodiment of my invention illustrating the welding of a head on the drum; Fig. 2 is an end View of Fig. 1 with certain parts omitted for clearness; Fig. 3 shows an arrange ment embodying means whereby thehtend known rill the .art ,and a. continuous line weld may beefi'ectively made withoutthe; use of upon the weld by reasonofthetendency of an electrodeto pick upmetalfrom' the work.

production of a longitudinaldap weld in curved 1 work.

Referring to Figs. 1 and 2, the work lisillustrated as a drum to which theheadj being pressed together. toforce the parts to beiweld'ed intointimatie contact at the point able manner inside the drum, the. arrangement shown embodying a channel member 5 secured to the supporting frame a 6, The

current is supplied. tothe weldingelectrodes.

3 and tfrom any suitable source in almanlner well-known intheart-.. As indicated in the drawing, one terminal 7 of the secondary:

. winding of a transformer is connected by the arrangement of apparatus which, Will 'en..- able circumferential ,welds'of the class de-j scribed-to be mademiithoutburning,the'work.

lead 'Sftothe electrode?) and the other termi- Any. suitable means may be provided for exerting pressure upon the work between the electrodes. .As illustrated the electrode a l is mounted on. a pivotedarm 10. The spring 11 and hand wheel 12 enable any desireddegree' of pressure to be obtained.

The electrode 3 is rotated by suitable power-operated means. In thev drawing, the electrode is shown as driven by the shaft 13 upon which is the worm wheel ll driven by aworm 15. The rotation o f the electrode causes the drum 1-to rotate about the electrode 3 and the electrode t turns simultaneously.

The pressure between the electrodesii and 4 is considerable and in order to produce uniformly successful welds I have found it necessary to apply power to rotate the opposite end of the drum at the-same speed that the: end being welded .is rotated. This is accomplished in the arrangement shown in Fig, l by a pair of Work engaging disks comprisinga roll 16 inside the drum cooperating with a rollv 17 outside the drum. If the drum is not driven at both ends. the undriven end tends to lag back slightly and the welding electrodes tend to cause the work to creep laterally. To reduce this creeping tendency to aminimum the rolls 16 and 17 are arranged to drive the drum at exactly the same speed as it is driven by the A. rotat smaller electrode in contact with the con more clearlyindicated.

BES'TAVAlLABLE COPY electrodes 3 and 4. The rolls are also pref- The matter just set forth will he more erably niade'aof the same material "as the elecclearly understood from Figs. 7 and-'8 which trodes and dressed'down to the same com for" simplicity illustrate" the weldingof a tact face so that they will provide thesame'pair of fiat sheets 18 and 19. T he larger coefiicient'of friction as the electrodes. electrode 20 is shown-in'contact with the; It will be observed that the electrode disk thinner sheet 18 and the smaller electrode 21 inside the drum is shown as of smaller in contact with the thicker sheet 19. The diameter than the electrode disk bearing'on electrode 20 is in this case also shown with a the outer surface of the drum. T his is an wider contact face than the electrode 21. It important feature of my invention. I have will be obse'rred that'the current density in discovered that a perfect weld may be made the work is greater in the thick sheet 19 both with the smaller electrode on the concave by' reason of'the smaller diameter of the side of the work .while a veryrougli and electrode 21 and the narrower contact face imperfect weld will be made if an attempt is thereof. In Figs. 7 and S tlie'tliickness of made to weld t :2 same work with the larger the work is exaggerated so thatthe spreadelectrode on the, concave side. llith the ing of the current through the work may he i vex side of the work', metal will be picked It is thus apparent that the current denup from thework by theelectrode and this sity in different parts ofthetwork is depend? difiiculty disappears fwhen' the arrangement ent not 'only'upon the relative diaii'i'eters' of ofjelectrodes is reversed. .I believe this to the electrodes butjlalsouponfthewidthiand be due to thelfact that the insid'e elec rode' shape of the contact races. fIt issoinetimes byreason' of. the curvature of the work has neessai'yto use electrodes bf dififer'e nt diam i a'lgreater area of, contactthan the outside: eters when weldingfiat worfi'whiclrconsists l electrode and therefore if the insideelec-f of sheetsof the same iiitit'ei ial lindthiclmessfim trode is-of thesaine orgreater size than the This m ay' be'necessary;firffiamplcflvliere outside electrode there a less area of 'condeeply corrugated sheets iir'e to b'eflw eldedj tactfa nd s gma-er ihirrent" density" and con; together between trialemt gatibfis:Insider seqiientlyjagreater heating'under the out to'permit of the highestpart"of"tlietvorl{ sidee'lect A cur'retit jsulticieiitly' large; clearingthe supporting axis ofthe eltictrode" 595 to weld thereforegreatly overheats the 'iiiate} I it may he nece'ssaryf td riizilte iiiiebfthe "e'lecrial in contaccwith the"outsidfielectrode.'1 trodes two ffeeti" or 'morefiii diafli'e'teri-thiisf" Thenecessary ditfereiice iii-the diameter of producing conttict'betweerr the el ectrodes depends upon the degree' of such. electrode" and'thesh' ewe hewel'dedl cur'vature bfjthe work and t'heappro'ximate In such casetlie'lsmall er lcti'ode will be dimensions necessary tdequalize'the heating given the reaterl'widtlf-of contact 'mayjbe' readily determined .by-those skilled Vs hil'e theLcurrent tends to spread'iii onef in the art from the principles here set forth. plane by. rcas'on of'thelarger 'dia'fnet'erof WVhere difi'eren't thicknesses ofthe same'contactsurface of one electrodeitfteiidsto" material are tob'e welded together'a further "sp'r'eadin the erases lane by"re'z'zsoi'i" of the" consideration shouldbe born'egin mind and I greatef width of contact 'siirface o'f the that is that the greater heatshould be.devel-. 1 smaller electrode. j The current densityfliii'd oped in= thethicker sheet and therefore for 'heating may thus" be' lniaintained "at"- the" flatwork the smallere'lectrode should be in proper value notwithstandingtlitfixessire contact with the thicker sheet and the larger diameter of cheer tlie 'eletrodesii i electrode in contact withthethinner sheet. Itis s ometiines desirable for anotheiire'a' lvhe'n'welding curred sheets, therefore, the 'son to'make the'contactfaces er the elec ent factors size of the electrodes should be proportioned trodes of differing width for the reason'that' with reference to the differing thicknesses where-both contact: faces are of the minimimi of material as well as with reference to the desired width anyfshifting or 'lateral move curvature of the work. lVhere sheets comment ofone contact fa'cewith' respect to the posed of metals of different specific resistother will change the density of the curances are to be welded the further 'consid-' rent in the areasof the-work which contact" eration 'must be borne in mind that the withthe electrodes.- An overheating of the smaller electrode should be placed in contact -metal in contact with the electrodes may with the material having the lower resistthereby occur causing the electrodes to'pick ance for flat work. hen metals of difl'er up metal from the work as heretofore. indient welding temperatures are to be united cated. In welding two sheets of the same the larger wheel should be placed against material and thickness the larger electrode the metal that welds at the lower temperamay therefore be made with anarrower conture. Where combinations of these difiertact face. Normally the greater arc of conare present, the electrodes will in tact possessed by the larger electrode will be each case be proportioned to give the nearest compensated for by the wider width of conapproximation to the correct welding tact possessed by the smaller electrode. The temperature. larger electrode ismore' apt to be sprung 1,601,927 BEST AVAlLABLE COP\ or distorted than the smaller electrode, but if eitherelectrode -shifts laterally with 'respect to the other, although the current density'at the face of the electrode having the wider surface of contact will be changed slightly, the density of current at the contact face of the narrower electrode will remain practicallythe same and overheating may be prevented, V

In the preceding discussion it has been assumed that the work is either flat or curved in the plane of the'electrode. The same principle, however, applies to a certain extent in making a weld where the work is curved trausverselyto the plane of the electrode. For example, such a weld is represented by the longitudinal scam in a drum or tank. Such welding is indicated in Fig. 9 where the overlapped sheets 22 and 23 to be welded are curved in a plane transverse to the'plaue of the electrodes 24 and It isappa-rent that the electrode 25 has a greater area of contact wi h the work than has the electrode 2 2. It is, therefore, desirable to dress the face ofthe electrode 25 slightly -'l e' improved. here the electrodes are of copper they tend to assume respectively convex and concave contact surfaces after they have been used for a short time since the copper is comparatively soft and is distorted after some use under pressure. By the time this desired contact surface has been-acquired, however, the contact surfaces may have become so irregular that it is.

necessary to redress the electrodes. It is, therefore, desirable that thecontactfaces of the electrodes be dressed to the desired curvature in the firstinstance.

Referring to Figs. 1 and 2, it will be observed that the electrode and work engaging disk inside .theklrum are of considerably smaller diameter than the drum. This construction is of further importance in that it permits-the-drum to rock slightly on the electrode and disk to accommodate irregi'ilarities in the work. If for example the drum is not, exactly round .or the curvature of the drum disappears fora. shortdistance the drum' will rock about the supporting wheels to accommodate such'irregularities. Small irregularities in the work may be ironed out by using an excessive pressure at the electrodes, but such pressure rapidly deforms the contact. surfacesand is furthen- -make ithe inside electrode approximately the .tendency of the drum to creep endwise is largely eliminated. If, however, a springing of one of the electrodes 01' some other cause tends to disturb the line of travel of the electrode, lateral creeping of the work may take place. If some arrangement is provided which prevents endwise movement of the drum' this creeping may. be prevented but only at the expense of subjecting the electrode to a considerable strain which reduces the length of time the electrode may be used without redressing. I, therefore, prefer to control the positionof the work by angular adjustment of the axiseither ofone ot the work engaging disk rolls .or one of the electrodes. This-means of correcting a.

tendency of the work to creep or move in a direction transverse totheline of welding as well as ameans foincozitrollingthe movement of the electrodes to secure-Weldingin a desired line forms thesubjectmatter of y vi o a pplica on, Seria l p- 9 filed January 5,' l925, a nd assigned to the same assignee as the present .application. Referring to Fig. 3;the roll 17' is mounted in a bearing, -the positionofwhich may be ju t y the hand whe l .2fi-qper t g through the ,worm"27 iandaworgn wheel 28. Any tendency of the worktocreep may be overcome byaslight angular adjustment of the'roll'l7 'and the desired line ofweld may be followed. w

In the embodiment. of my inventignshown in Fig. t-means are provided for automatically preventing creeping otthe'rwork. In

the arrangement shown the angular adjust ability ;is.japplie dto'fthe; electrode A". The angular. position o this electrode is con-- trolled by the.;rno tor- 29 drivingqthe worm heel 28-. hr ng the-y ltm 2 lhe pe tionof themotor is controlled by a suitable circuit controlling contact 30 carrying a shoe or roller 31 adapted to be pressedagainst the edge: of the Work .by spring 32., .When the work tends to nrove laterally the contact 30 will engage either the contact 33 or the contact-34 to causethe motor 29 to rotate in onedirection or the other. In the arrangement diagrammatically indicated the contacts 33and 3 4-areconnected to thereversely wound motor field windings .35 and 36. The motor 29. may be supplied from any suitable source {indicated for simplicity a battery 37. Fig. eshows. the. electrode 3 and roll 16 as drivenby gears 38 ad 3.9. respectively engaged by gears 40 and t1 mounted on a shaft 42,-which' may be. driven by any suitable powenoperated means- Y The'operation of the arrangement shown in Fig. 4 will be obvious from what has been heretofore set forth. hen the work is in the proper position with respect to the electrodes, the contact will lie in between the contacts 33 and 34 and the motor 29 will stand still. If the work tends to move endwise one way or the other, the motor 29 will he energized and dperated in the proper direction to adjust the angular position of the electrode 4 so as to correct the tendency of the work to creep endwisc. It is apparent that the roller 31 may be arranged to engage either'end of the drum or may be arranged to engage a guiding flange which may he clamped in any desired position to the drum. Where a separate flange is clamped on in the manner indicated. it is apparent that the line of the weld will be governed by the contour of the flange which may he predetermined to giveany desired line of weld. The pplication of the invention is not limited to circum't'crentia-l welding since the same arrangement may be applied to the welding of flat work in which case the shoe or roller 31 \Vill" engage either the edge of one of the sheets'to'be' welded or a guiding flange suit ably clamped to one of the sheets.

- In certain cases the production of a spiral weldmay be desirablefifFig. 5 illustrates how the automati'c"arrangement ofFig. 4

may be arranged so as to produce a spiral weld of any desired pitch. In Fig. 5 the work, isindicatcd as comprising two drums orshells 43 and 44 which are to be welded together bya spiral weld. 45 and 46 indicate either a pair of electrodes or a pair of guiding "rolls. 'The' contact-making device comprrsrngthe contactsBO, 33 and 34 and the shoe orfroll 31rf1s1n this case shown as comprising -a' member 47 arranged to 'be moved long tudinally by means o'f-a screw 48 driven by means of adjustable speed gear-' ing from the shaft'49' upon whichthe roll 45 is mountedi Theadjustable' speed gearing shown comprises cone'pulley '50 on the shaft"49"and acone pulley 51 driving the shaft 48 and" abelt 52, the position of which alon the pulleys may be adjusted by any suitable'means i 1 I The operation of the arrangement shown in Fig; 5 would be the sameas the operation of the arrangement shown in Fig.4 if thescrew48 did not turn. Since, however, thisscrew is driven from the shaft 49 it follows that the device 47 carrying the contact shoeorroller 31 moves longitudinally over the surface of the drum. This causes the motor controlledby thecontacts 30, 33 and 34 to adjust the angular position of the roll controlling creeping so as to cause the work to move endwise thus producing a spiral line of weld. The pitchot' the spiral is dependent upon the speed relationship between the shafts 48 and 49 and by adjusting the belt BEST AVAILABLE COF\ along the faces-of the cone pulleys 50 and 51 this speed relationship may be adjusted to give the desired pitch.

Fig.6 shows a modification of my invention in which the two ends 54-and 55 are ar--- in the arrangement of Figs. 3 or 4. A transformer 68 is indicated for supplying current to theelectrodes 64 and 57 and a transformer 69 2s indicated-for supplying current to the electrodes sand 58. Suitable insulation i will iniall-ca'ses be provided for confining the current to the desired path in a manner well known in the art.

' It will'be obvious to those skilled" the art that--.many modifications and variations of the arrangements shown-are possible andin the appended claims Lintend-to cover all such modifications. aslbfall-within the true spirit of invention. 7'; i s Vhat Icl-aim as-new'and desire to'secure-byiLetters-Batent of the United States,

1. The method be operating-:a welding machine of the type 'comprising a-pair of rotatabledisk electrodes arranged to en gage the work fromopposite sides local 4 arcs" of contact i and conduct welding current through therwork while: the electrodes and work: are'rmo'ving relatively :to produce a lineiweld infcurvd avorkand wherein the contact"-surfaceso-i the electrodes are di-fferently curved so that-tlie-atcs-bf contact.

between i the respective electrodes:; and the the cones we. side of i thes wvo'rlg characterized by the fact that'the work is placed between I work depends upon whichelectr'odeengages the i electrodes with: f the l electrode :of r-the 2 greater-{curvature engaging :the concaveside of'the'worlewhile"maintaining the areas' of contact between'the electrodes and the work substantially equahfso 1 as substantially to equalize the heating under the electrbdes'.

2; The method of producing a circumferential lineweld in curved work which comprises passing the 'work between apair of rotata ble disk electrodes having-differentdiameters each engaging the'work in a-local arc of contact with the electrode of smaller diameter in eontac'twith the concave side of the work while maintaining the areas'ofthe local arcs'of contact of such' relative values that the heatin under the electrodes is substantially equalized; 1

3. A welding machine for producing circumferential welds in curved work of the type wherein a pair of rotatable disk electrodes are arranged to contact in local arcs of cont-act with opposite sides of the work and lead welding current through the work while the electrodes and work are moving relatively to produce a line weld, characterized by the fact that the electrodes are of different diameters and by the fact that the electrode arranged to engage the concave surface of the work has a greater degree of curvature than the work said electrodes being arranged to engage the work in local arcs of contact, having a contact area such as substantially to equalize the heating under the electrodes.

4. A welding machine for producing circumferential welds in drum work comprising a pair of rotatable disk electrodes adapted to contact respectively with the inside and outside surfaces of the work and conduct welding current through the work, a pair of work engaging disks spaced laterally from said electrodes and adapted to BEST AVAILABLE com 5 contact respectively with the inside and outside surfaces of the work, the inside electrode and inside work engaging disk being of smaller diameter than the work whereby the work may be supported upon and rock about said disks to accommodate irregularities in the contour of the work, and means for driving one of said electrodes and one of said work engaging disks to move the work relatively to the electrodes to produce a line weld, said work engaging disks being arranged to impart the same speed of movement to the work as is imparted by the electrodes.

5. A welding machine as claimed in claim 4 characterized by the fact that the work engaging disks also constitute electrodes to conduct welding current through the work whereby two circumferential welds may be made simultaneously.

In witness whereof, I have hereunto set my hand this 23rd day of August, 1923.

HARRY TOBEY. 

